Prince William, Prince George, Princess Charlotte and Kate Middleton
Prince William, Prince George, Kate Middleton and Princess Charlotte arrive at the Victoria Airport on Sept. 24, 2016 in Victoria, Canada. Getty Images/Chris Jackson

Prince William fears for the future of his children.

The Duke and Duchess of Cambridge are parents to three adorable royal kids, Prince George, 5, Princess Charlotte, 3, and Prince Louis, 1. In a new book on conservation entitled “The Last Elephants,” Prince William expressed his concerns over how the number of elephants significantly dropped from millions to only thousands in the past 35 years at the hands of poachers, criminal gangs and traffickers.

The royal dad of three finds it heartbreaking that he has to explain this thing to his children.

“At the current pace of illegal poaching, when Charlotte turns 25 the Africa elephant could be gone from the wild,” Prince William wrote, quoting the Great Elephant Census.

“I’m not prepared to be part of a generation that lets these iconic species disappear and have to explain to our children why we lost this battle when we had the tools to win it.”

It wasn’t the first time for Prince William to open up about animal extinction and his kids. Back in October, when he visited Africa and delivered a speech in front of 1,000 delegates from 82 countries, he also touched the issue of animal extinction relative to his kids.

The future king said that it was heartbreaking to think that by the time all of his children are in their 20s, the elephants, rhinos and tigers might be extinct in the wild. He admitted that he couldn’t imagine himself looking his kids in the eye and admitting that he was part of the generation that allowed it to happen.

Prince William believed that it’s time to end the illegal wildlife trade. He was convinced that it was carried out by ruthless cross-border criminal networks and was fueled by corruption.

Back in September, Prince William revealed Prince George and Princess Charlotte’s favorite bedtime story at a conservation event. The Duke of Cambridge told Julia Donaldson and Axel Scheffler that his kids love “The Gruffalo.”

He added that Prince George was overjoyed to see the rhino statues displayed for Tusk Rhino Trail event from the windows and joked that it’s a good thing the third-in-line to the throne didn’t know it was for sale otherwise he would be “keeping an eye on it.”